Remove pg_dump/pg_dumpall support for dumping from pre-9.2 servers.

Per discussion, we'll limit support for old servers to those branches
that can still be built easily on modern platforms, which as of now
is 9.2 and up.  Remove over a thousand lines of code dedicated to
dumping from older server versions.  (As in previous changes of
this sort, we aren't removing pg_restore's ability to read older
archive files ... though it's fair to wonder how that might be
tested nowadays.)  This cleans up some dead code left behind by
commit 9895961.

Discussion: https://postgr.es/m/2923349.1634942313@sss.pgh.pa.us

Author: tglsfdc

doc/src/sgml/ref/pg_dump.sgml

@@ -398,16 +398,6 @@ PostgreSQL documentation
         different worker jobs wouldn't be guaranteed to see the same data in
         each connection, which could lead to an inconsistent backup.
        </para>
-       <para>
-        If you want to run a parallel dump of a pre-9.2 server, you need to make sure that the
-        database content doesn't change from between the time the leader connects to the
-        database until the last worker job has connected to the database. The easiest way to
-        do this is to halt any data modifying processes (DDL and DML) accessing the database
-        before starting the backup. You also need to specify the
-        <option>--no-synchronized-snapshots</option> parameter when running
-        <command>pg_dump -j</command> against a pre-9.2 <productname>PostgreSQL</productname>
-        server.
-       </para>
       </listitem>
      </varlistentry>
 
@@ -945,9 +935,10 @@ PostgreSQL documentation
       <term><option>--no-synchronized-snapshots</option></term>
       <listitem>
        <para>
-        This option allows running <command>pg_dump -j</command> against a pre-9.2
-        server, see the documentation of the <option>-j</option> parameter
-        for more details.
+        This option allows running <command>pg_dump -j</command> against a
+        pre-v10 standby server, at the cost of possibly producing an
+        inconsistent dump.  See the documentation of the <option>-j</option>
+        parameter for more details.
        </para>
       </listitem>
      </varlistentry>
@@ -1381,7 +1372,7 @@ CREATE DATABASE foo WITH TEMPLATE template0;
    <productname>PostgreSQL</productname> server versions newer than
    <application>pg_dump</application>'s version.  <application>pg_dump</application> can also
    dump from <productname>PostgreSQL</productname> servers older than its own version.
-   (Currently, servers back to version 8.0 are supported.)
+   (Currently, servers back to version 9.2 are supported.)
    However, <application>pg_dump</application> cannot dump from
    <productname>PostgreSQL</productname> servers newer than its own major version;
    it will refuse to even try, rather than risk making an invalid dump.

src/bin/pg_dump/dumputils.c

@@ -227,10 +227,6 @@ buildACLCommands(const char *name, const char *subname, const char *nspname,
 				appendPQExpBuffer(firstsql, "%s FROM ", name);
 				if (grantee->len == 0)
 					appendPQExpBufferStr(firstsql, "PUBLIC;\n");
-				else if (strncmp(grantee->data, "group ",
-								 strlen("group ")) == 0)
-					appendPQExpBuffer(firstsql, "GROUP %s;\n",
-									  fmtId(grantee->data + strlen("group ")));
 				else
 					appendPQExpBuffer(firstsql, "%s;\n",
 									  fmtId(grantee->data));
@@ -247,14 +243,9 @@ buildACLCommands(const char *name, const char *subname, const char *nspname,
 	 * public privileges are added in new versions: the REVOKE ALL will revoke
 	 * them, leading to behavior different from what the old version had,
 	 * which is generally not what's wanted.  So add back default privs if the
-	 * source database is too old to have had that particular priv.
+	 * source database is too old to have had that particular priv.  (As of
+	 * right now, no such cases exist in supported versions.)
 	 */
-	if (remoteVersion < 80200 && strcmp(type, "DATABASE") == 0)
-	{
-		/* database CONNECT priv didn't exist before 8.2 */
-		appendPQExpBuffer(firstsql, "%sGRANT CONNECT ON %s %s TO PUBLIC;\n",
-						  prefix, type, name);
-	}
 
 	/*
 	 * Scan individual ACL items to be granted.
@@ -306,10 +297,6 @@ buildACLCommands(const char *name, const char *subname, const char *nspname,
 					appendPQExpBuffer(thissql, "%s TO ", name);
 					if (grantee->len == 0)
 						appendPQExpBufferStr(thissql, "PUBLIC;\n");
-					else if (strncmp(grantee->data, "group ",
-									 strlen("group ")) == 0)
-						appendPQExpBuffer(thissql, "GROUP %s;\n",
-										  fmtId(grantee->data + strlen("group ")));
 					else
 						appendPQExpBuffer(thissql, "%s;\n", fmtId(grantee->data));
 				}
@@ -322,10 +309,6 @@ buildACLCommands(const char *name, const char *subname, const char *nspname,
 					appendPQExpBuffer(thissql, "%s TO ", name);
 					if (grantee->len == 0)
 						appendPQExpBufferStr(thissql, "PUBLIC");
-					else if (strncmp(grantee->data, "group ",
-									 strlen("group ")) == 0)
-						appendPQExpBuffer(thissql, "GROUP %s",
-										  fmtId(grantee->data + strlen("group ")));
 					else
 						appendPQExpBufferStr(thissql, fmtId(grantee->data));
 					appendPQExpBufferStr(thissql, " WITH GRANT OPTION;\n");
@@ -420,16 +403,12 @@ buildDefaultACLCommands(const char *type, const char *nspname,
 /*
  * This will parse an aclitem string, having the general form
  *		username=privilegecodes/grantor
- * or
- *		group groupname=privilegecodes/grantor
- * (the "group" case occurs only with servers before 8.1).
  *
  * Returns true on success, false on parse error.  On success, the components
  * of the string are returned in the PQExpBuffer parameters.
  *
- * The returned grantee string will be the dequoted username or groupname
- * (preceded with "group " in the latter case).  Note that a grant to PUBLIC
- * is represented by an empty grantee string.  The returned grantor is the
+ * The returned grantee string will be the dequoted username, or an empty
+ * string in the case of a grant to PUBLIC.  The returned grantor is the
  * dequoted grantor name.  Privilege characters are translated to GRANT/REVOKE
  * comma-separated privileges lists.  If "privswgo" is non-NULL, the result is
  * separate lists for privileges with grant option ("privswgo") and without
@@ -522,8 +501,7 @@ do { \
 			{
 				CONVERT_PRIV('d', "DELETE");
 				CONVERT_PRIV('t', "TRIGGER");
-				if (remoteVersion >= 80400)
-					CONVERT_PRIV('D', "TRUNCATE");
+				CONVERT_PRIV('D', "TRUNCATE");
 			}
 		}
 

src/bin/pg_dump/pg_backup_archiver.c

@@ -904,13 +904,10 @@ restore_toc_entry(ArchiveHandle *AH, TocEntry *te, bool is_parallel)
 						StartTransaction(&AH->public);
 
 						/*
-						 * If the server version is >= 8.4, make sure we issue
-						 * TRUNCATE with ONLY so that child tables are not
-						 * wiped.
+						 * Issue TRUNCATE with ONLY so that child tables are
+						 * not wiped.
 						 */
-						ahprintf(AH, "TRUNCATE TABLE %s%s;\n\n",
-								 (PQserverVersion(AH->connection) >= 80400 ?
-								  "ONLY " : ""),
+						ahprintf(AH, "TRUNCATE TABLE ONLY %s;\n\n",
 								 fmtQualifiedId(te->namespace, te->tag));
 					}